The occipital bone in Primates. 75 



condyle an invariable character in birds and reptiles. In the latter, 

 one may have a quadripartite condition. It was shown by Cleland 

 that the condyles in relation to the occipital bone vary with the age. 

 In a young Polar bear the condyles are continued across the median 

 line in front by a narrow articular tract. Changes obviously due to 

 age may be seen in several mammalian groups. The condyles in man 

 contrast with those in the Gorilla. The character of the former 

 is due probably to the erect attitude of man to which Turner 

 alludes. 



There is a condyle mesially in man like that mentioned by Drs. 

 Reichert and Strecker. The diameter of the basilar may be compared 

 with the antero-posterior diameter of the foramen. A foramen is 

 basilar in one gorilla. 



The occipital bone in Lemur Catta, a young specimen, is 2.9 cms. 

 sTiortest distance from before back, and 2.4 cms. from side to side. 

 Ant-post-basilar 1.2 cms. Foramen magnum 1.2 cms. ant. post, and 

 1.2 cms. from side to side. It is lozenge-shaped. Foramen to middle 

 of central elevation (occ. protub.) 1.3 cms. Centre of median elevation 

 corresponding to the internal fossa, for middle cerebellar prominence, 

 to anterior superior angle 1.3 cms. The condyles are 3 mm. apart 

 in front, 1.7 cms. apart behind. The condyles are 1 cm. each long, 

 and 2 mm. each broad. The elevation corresponding to the internal 

 fossa 1.3 cms from above down, and 4 mms. transversely. The curved 

 lines on each side are connected with the elevation above the middle. 

 The lines are continued laterally to the side, each gives a branch off, 

 that runs forward along the temporal fossa, above the zygoma a 

 second is directed down to the rim of the external auditory meatus. 

 The posterior root of the zygoma arises between these two, and comes 

 up close to the ridge near the middle. Two rounded eminences are 

 found below the curved lines, each lies between the curved line of its 

 own side, the median elevation and the foramen magnum. These 

 correspond to fossae on the internal (Cerebellar) surface. The bone 

 is thin here, and in the middle line. It is very translucent in the 

 fossae, and along the sutures, and thinner where the fossae are than 

 elsewhere. 



